6.0l fuel press

[Wilson]

Sorry long question- I know fuel press is supposed to be around 45-50psi on factory pump/ diesel fuel.

Well I decided to change my filter today and install a fuel press gauge. I installed an autometer electric sender that I 't'd into the 3/8" line before it splits to the heads.

Well I got it all wired up and turned the key and I have pressure, unfortunately it's 36psi according to the gauge. And when I rap the throttle it drops a couple psi.

Havent even tried the veggie side yet as Im so freaked out and the truck is cold...Hoping that reads low too so it's a gauge issue not my diesel side or my injectors will be toast at that psi correct?

FYI this is an old sender from my car so ??? or maybe there is air in the line? Maybe gauge is incorrect??? HELP!

I have changed a few filters on this rig (like every 9-10k)so I don't think theres a issue there???

[Wilson]

ok just ran it up to temp.. looks like 37psi idle


switched to wvo and pegged the gauge lol 100+psi. I am hoping bad electrical sender. I did turn in the v3 press screw like 1 full turn from factory a few weeks ago..

any thoughts?

[Wilson]

Err- I just realized what I did. When I put the new filter in for some reason I didn't push it on the cap first. I remember putting the filter in the housing and then putting the cover on.

I'm sure that's it... now I gotta go outside in the cold. That's what I get for being in a hurry earlier.

[Hooter]

Glad you figures it out... Good news is you will probably never make that mistake again.

[Wilson]

Yeah, In fact I still don't know why I did it the first time...I guess I just rushed and didn't think it would matter.

Anyway It now reads better, like 41-42psi at idle. Should still be higher from what i think i've read...



Now I need to look into that AND dial down the veggie pressure some.

[Marv]

Now I need to look into that AND dial down the veggie pressure some.

Yeah, 100+ psi is a lot!!

However, I have found that the system seems to work better with the pressure set slightly higher than the stock DFA setting.

Mine is right at 75psi now.

[FastCote]

Yeah, 100+ psi is a lot!!

However, I have found that the system seems to work better with the pressure set slightly higher than the stock DFA setting.

Mine is right at 75psi now.

I think 75 psi IS the stock DFA setting. At least mine came that way (more like 78 psi).

[Marv]

I think 75 psi IS the stock DFA setting. At least mine came that way (more like 78 psi).

You could very well be right. I know Jason told me two full turns back in (after taking it all the way out) which netted me right at 65psi. So, mine could have been off just a tad for some reason.

Either way, with 2 1/4 turns (and 75 psi), the system does seem to work much better.

With my luck, I probably just jinxed myself...LOL.

[Wilson]

ok after driving it a couple miles it idles around 48-50psi on diesel... but under a load I still can see 35-40psi.

Is my diesel pump bad or what?

I know you guys have gauges!!!

[Jack_Toepfer]

ok after driving it a couple miles it idles around 48-50psi on diesel... but under a load I still can see 35-40psi.

Is my diesel pump bad or what?

I know you guys have gauges!!!

I think the consensus was that the diesel pump is a weak POS and you'll see pressure drop under load. On the WVO, I guess they aren't seeing as drastic of a drop.

[Wilson]

I think the consensus was that the diesel pump is a weak POS and you'll see pressure drop under load. On the WVO, I guess they aren't seeing as drastic of a drop.

yep, i guess i am just alarmed now that i see whats going on hehe. I was just chugging along blindly without the gauge!

[Wilson]

btw,
On WVO, during an hour trip I was able to get it down to about 50psi pulling a LONG(about 3mi) 25%+ grade... Long amount of time close to 3krpm

What do you guys see on WVO under large loads?

Stock calibration btw

[Clay]

Your pump will go out like a light bulb when it goes probably...your FPR probably needs tweeked.
I am not comfortable with anything below 53-55 psi (diesel) and on vegi my pressure never drops more than a few (5-6) lbs on WOT. I would have a dealer check stock pressure and when they see it that low, they will offer to take your money to change the FPR but its fairly easy to do yourself.
Adjust your vegi pressure up to 75 ish and you will be fine.

[Wilson]

thanks clay... yeah I guess I'll have it looked at.

I think the large WVO pressure drop I am seeing is due to clogging donaldson filter. It's my first filter and about 3kmi so...?

[Clay]

I am not comfortable with anything below 53-55 psi (diesel)

I should have stated why...according to lots of diesel techs i have asked, low fuel pressure (below 45) will begin knocking out injectors. They need the pressure to keep the plunger inside them from "bouncing". If it bounces, it will destroy the internal seal and begine internally leaking fuel into your crank case through the valve cover area.